The present invention relates to an energy recovery system for recovering and utilizing exhaust energy from an internal combustion engine.
Engine cooling systems consume significant amounts of power. For example, for cost reasons, fixed blade fans are sized for the heaviest cooling load condition. As a result, during light load operation several kilowatts (kW) of engine output power are being wasted. At rated conditions, it is typical for five percent of the engine power to be used to drive the cooling fan, and for 1 to 2 kW to be used to drive the water pump.
Modern turbochargers provide charge air boost pressure by utilizing energy being exhausted from the engine. Considerable unused energy is available from the exhaust gasses because the turbine is normally sized only to provide needed charge air.
Accordingly, an object of this invention is to provide a system for utilizing exhaust energy of an internal combustion engine which would otherwise be wasted.
A further object of the invention is to use the exhaust energy of an engine to operate cooling system components.
These and other objects are achieved by the present invention, wherein an energy recovery system for an internal combustion engine includes a turbocharger unit having an turbocharger turbine receiving exhaust from the engine and a second turbine driven by the exhaust gasses. The second turbine drives an electrical generator. The generator supplies electrical power to an electrical control unit, which supplies power to an electric fan motor which drives an engine cooling fan. The control unit also supplies electrical power to an electric coolant pump motor which drives an engine coolant pump. The turbine is preferably a variable geometry turbine whose geometry is controlled so that its power absorption matches the electrical load of the generator. The system may also include a turbine bypass valve or wastegate which provides turbine overspeeding.